<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/xhtml;charset=UTF-8"/>
<meta http-equiv="X-UA-Compatible" content="IE=9"/>
<title>Technical data and limitations</title>
<title>CMSIS-FreeRTOS: Technical data and limitations</title>
<link href="tabs.css" rel="stylesheet" type="text/css"/>
<link href="cmsis.css" rel="stylesheet" type="text/css" />
<script type="text/javascript" src="jquery.js"></script>
<script type="text/javascript" src="dynsections.js"></script>
<script type="text/javascript" src="printComponentTabs.js"></script>
<link href="navtree.css" rel="stylesheet" type="text/css"/>
<script type="text/javascript" src="resize.js"></script>
<script type="text/javascript" src="navtree.js"></script>
<script type="text/javascript">
  $(document).ready(initResizable);
  $(window).load(resizeHeight);
</script>
<link href="search/search.css" rel="stylesheet" type="text/css"/>
<script type="text/javascript" src="search/search.js"></script>
<script type="text/javascript">
  $(document).ready(function() { searchBox.OnSelectItem(0); });
</script>
</head>
<body>
<div id="top"><!-- do not remove this div, it is closed by doxygen! -->
<div id="titlearea">
<table cellspacing="0" cellpadding="0">
 <tbody>
 <tr style="height: 46px;">
  <td id="projectlogo"><img alt="Logo" src="CMSIS_Logo_Final.png"/></td>
  <td style="padding-left: 0.5em;">
   <div id="projectname">CMSIS-FreeRTOS
   &#160;<span id="projectnumber">Version 9.0.0</span>
   </div>
   <div id="projectbrief">CMSIS-RTOS2 compliant FreeRTOS Implementation</div>
  </td>
 </tr>
 </tbody>
</table>
</div>
<!-- end header part -->
<div id="CMSISnav" class="tabs1">
    <ul class="tablist">
      <script type="text/javascript">
		<!--
		writeComponentTabs.call(this);
		//-->
      </script>
	  </ul>
</div>
<!-- Generated by Doxygen 1.8.6 -->
<script type="text/javascript">
var searchBox = new SearchBox("searchBox", "search",false,'Search');
</script>
  <div id="navrow1" class="tabs">
    <ul class="tablist">
      <li><a href="index.html"><span>Main&#160;Page</span></a></li>
      <li class="current"><a href="pages.html"><span>Usage&#160;and&#160;Description</span></a></li>
      <li><a href="modules.html"><span>Reference</span></a></li>
      <li>
        <div id="MSearchBox" class="MSearchBoxInactive">
        <span class="left">
          <img id="MSearchSelect" src="search/mag_sel.png"
               onmouseover="return searchBox.OnSearchSelectShow()"
               onmouseout="return searchBox.OnSearchSelectHide()"
               alt=""/>
          <input type="text" id="MSearchField" value="Search" accesskey="S"
               onfocus="searchBox.OnSearchFieldFocus(true)" 
               onblur="searchBox.OnSearchFieldFocus(false)" 
               onkeyup="searchBox.OnSearchFieldChange(event)"/>
          </span><span class="right">
            <a id="MSearchClose" href="javascript:searchBox.CloseResultsWindow()"><img id="MSearchCloseImg" border="0" src="search/close.png" alt=""/></a>
          </span>
        </div>
      </li>
    </ul>
  </div>
</div><!-- top -->
<div id="side-nav" class="ui-resizable side-nav-resizable">
  <div id="nav-tree">
    <div id="nav-tree-contents">
      <div id="nav-sync" class="sync"></div>
    </div>
  </div>
  <div id="splitbar" style="-moz-user-select:none;" 
       class="ui-resizable-handle">
  </div>
</div>
<script type="text/javascript">
$(document).ready(function(){initNavTree('tech_data.html','');});
</script>
<div id="doc-content">
<!-- window showing the filter options -->
<div id="MSearchSelectWindow"
     onmouseover="return searchBox.OnSearchSelectShow()"
     onmouseout="return searchBox.OnSearchSelectHide()"
     onkeydown="return searchBox.OnSearchSelectKey(event)">
<a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(0)"><span class="SelectionMark">&#160;</span>All</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(1)"><span class="SelectionMark">&#160;</span>Functions</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(2)"><span class="SelectionMark">&#160;</span>Groups</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(3)"><span class="SelectionMark">&#160;</span>Pages</a></div>

<!-- iframe showing the search results (closed by default) -->
<div id="MSearchResultsWindow">
<iframe src="javascript:void(0)" frameborder="0" 
        name="MSearchResults" id="MSearchResults">
</iframe>
</div>

<div class="header">
  <div class="headertitle">
<div class="title">Technical data and limitations </div>  </div>
</div><!--header-->
<div class="contents">
<div class="textblock"><p>This lists the technical data of CMSIS-FreeRTOS.</p>
<h1><a class="anchor" id="td_limitations"></a>
Limitations</h1>
<p>The following list briefly describes the limitations and unsupported features of the CMSIS-RTOS2 wrapper for FreeRTOS:</p>
<ul>
<li>ARM Compiler v6 is not supported by FreeRTOS, yet.</li>
<li>Static memory allocation will only work if <em>all</em> memory (from attributes structure) is provided statically. In order to allocate object memory statically, you need to:<ul>
<li>provide the memory for control blocks and stack in the <code>osThreadAttr_t</code> structure for threads.</li>
<li>provide the memory for control blocks and message data in the <code>osMessageQueueAttr_t</code> structure for memory queues.</li>
<li>provide the memory for control blocks for other objects in the object's attributes structure.</li>
</ul>
</li>
<li>Each timer object requires additional 8 bytes of dynamic memory.</li>
<li><code>osKernelSuspend</code> and <code>osKernelResume</code> are not supported.</li>
<li><code>osKernelGetTickCount</code> is limited to a 32-bit return value.</li>
<li><code>osThreadDetach</code>, <code>osThreadJoin()</code> and attribute <code>osThreadJoinable</code> are not supported (<code>osThreadNew</code> returns NULL when osThreadJoinable attribute is specified).</li>
<li><code>osThreadGetStackSize</code> is not implemented.</li>
<li>Event flags are limited to 24 bits.</li>
<li><code>osEventFlagsGetName</code> is not implemented.</li>
<li><code>osEventFlagsWait</code> cannot be called from an ISR.</li>
<li>Priority inherit protocol is used as default mutex behavior (<code>osMutexNew</code> creates priority inherit mutex object by default and ignores <code>osMutexPrioInherit</code> attribute when specified).</li>
<li>Robust mutex objects are not supported (<code>osMutexNew</code> returns NULL when <code>osMutexRobust</code> attribute is specified).</li>
<li><code>osMutexGetName</code> is not implemented and always returns NULL.</li>
<li><code>osSemaphoreGetName</code> is not implemented and always returns NULL.</li>
<li>Memory Pool functions are not implemented and will always return with error.</li>
<li><code>osMessageQueueGetName</code> is not implemented and always returns NULL.</li>
<li><code>osMessageQueuePut</code> and <code>osMessageQueueGet</code> always ignore message priority.</li>
</ul>
<h1><a class="anchor" id="td_validation"></a>
CMSIS-RTOS validation suite results</h1>
<p>CMSIS provides a <a href="http://arm-software.github.io/CMSIS_5/RTOS2/html/rtosValidation.html" target="_blank">validation suite</a> that can be used to test a real-time operating system for compliance to the standard. The test suite has been run successfully on the CMSIS-FreeRTOS implementation with the following exceptions:</p>
<p><b>TC_ThreadParam:</b> </p>
<ul>
<li>Reason: unsupported feature</li>
<li>Test attempts to test <code>osThreadJoin</code> and <code>osThreadDetach</code> functions for invalid parameter input. These two functions are not implemented.</li>
</ul>
<p><b>TC_ThreadInterrupts:</b> </p>
<ul>
<li>Reason: unsupported feature</li>
<li>Test attempts to call <code>osThreadJoin</code> and <code>osThreadDetach</code> from the ISR. These two functions are not implemented.</li>
</ul>
<p><b>TC_EventFlagsInterrupts:</b> </p>
<ul>
<li>Reason: unsupported feature</li>
<li>Test attempts to call <code>osEventFlagsWait</code> from the ISR. Wrapper implementation does not allow function <code>osEventFlagsWait</code> to be called from interrupts.</li>
</ul>
<p><b>TC_MutexRobust:</b> </p>
<ul>
<li>Reason: unsupported feature</li>
<li>Test attempts to create robust mutex. FreeRTOS implementation does not support robust mutexes.</li>
</ul>
<p><b>TC_MutexOwnership:</b> </p>
<ul>
<li>Reason: unsupported feature</li>
<li>Test attempts to release a mutex from a thread which is not the mutex owner. Test fails, because FreeRTOS implementation does not verify ownership on mutex release. </li>
</ul>
</div></div><!-- contents -->
</div><!-- doc-content -->
<!-- start footer part -->
<div id="nav-path" class="navpath"><!-- id is needed for treeview function! -->
  <ul>
    <li class="footer">Generated on Mon Mar 13 2017 09:48:26 for CMSIS-FreeRTOS by ARM Ltd. All rights reserved.
	<!--
    <a href="http://www.doxygen.org/index.html">
    <img class="footer" src="doxygen.png" alt="doxygen"/></a> 1.8.6 
	-->
	</li>
  </ul>
</div>
</body>
</html>
